Need a Battery charger

I have an old one on wheels that I pulled off the curb on trash day 30 years ago. Still works awesome. The timer doesn't work so you have to pay attention.
I worked for a trucking company in the 80's. We used one for testing trailer lights. Drivers would damage the marker lights hitting tree branches all the time. I have to say sometimes the charger was hooked up for hours as we were interrupted during the job to be pulled off for some other work. Yeah, our timer was broke too. Worked for us !